His legs have different thickness, which looks weird
I suggest you make the light-source come from the viewer's direction and not from the side, since the whole light source will flip when he turns around - not so hot.
His skin tones are very unnatural - make them more orangey and less pinky - but make sure he doesn't turn ORANGE per se. First finding a balance between pink and orange that you like would be a good step in selecting a good skin colour - then fiddling with saturation until it looks natural. Use my edit as some kind of reference, possibly (I think Arne would be able to give better crits on skin color, ehehehehehehe. I'll link you to the tutorial that explains the stuff.
http://www.itchstudios.com/psg/art_tut.htm#skin_tones )
are his hands and face supposed to have different colours? if not, unify them.
Shading still feels a bit all over the place, make sure that the different bits of shading aren't just dots here and there - that'll create noise. And, paradoxally, some 'outlines' or just some underlining of the darkest shades with one dark colour would help unify this piece. Or why not use the same dark colour for his pants and his arm guards? The saturation is overall quite high in the shadows, making the thing feel a bit surreal. Beef up the saturation and brightness in his highlights and gray-ify his shadows a little bit!
http://www.itchstudios.com/psg/art_tut.htm <- and read this, just read it and let it sink in, this tutorial is so damn good. It'll help you THINK about art just in general.
Also good luck guy, I love the way you're making constant progress and listening to our advice, compels me to help you even more.